Article
11/18/2011

List<T>.InsertRange Method

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Inserts the elements of a collection into the List<T> at the specified index.

Namespace: System.Collections.Generic
Assembly: mscorlib (in mscorlib.dll)

Syntax

'Declaration
Public Sub InsertRange ( _
    index As Integer, _
    collection As IEnumerable(Of T) _
)

public void InsertRange(
    int index,
    IEnumerable<T> collection
)

Parameters

index
Type: System.Int32
The zero-based index at which the new elements should be inserted.

collection
Type: System.Collections.Generic.IEnumerable<T>
The collection whose elements should be inserted into the List<T>. The collection itself cannot be nulla null reference (Nothing in Visual Basic), but it can contain elements that are nulla null reference (Nothing in Visual Basic), if type T is a reference type.

Exceptions

Exception	Condition
ArgumentNullException	collection is nulla null reference (Nothing in Visual Basic).
ArgumentOutOfRangeException	index is less than 0. -or- index is greater than Count.

ArgumentNullException

collection is nulla null reference (Nothing in Visual Basic).

ArgumentOutOfRangeException

index is less than 0.

-or-

index is greater than Count.

Remarks

List<T> accepts nulla null reference (Nothing in Visual Basic) as a valid value for reference types and allows duplicate elements.

If the new Count (the current Count plus the size of the collection) will be greater than Capacity, the capacity of the List<T> is increased by automatically reallocating the internal array to accommodate the new elements, and the existing elements are copied to the new array before the new elements are added.

If index is equal to Count, the elements are added to the end of List<T>.

The order of the elements in the collection is preserved in the List<T>.

This method is an O(n + m) operation, where n is the number of elements to be added and m is Count.

Examples

The following code example demonstrates InsertRange method and various other methods of the List<T> class that act on ranges. After the list has been created and populated with the names of several peaceful plant-eating dinosaurs, the InsertRange method is used to insert an array of three ferocious meat-eating dinosaurs into the list, beginning at index location 3.

Imports System.Collections.Generic

Public Class Example

   Public Shared Sub Demo(ByVal outputBlock As System.Windows.Controls.TextBlock)

      Dim input() As String = {"Brachiosaurus", _
                                "Amargasaurus", _
                                "Mamenchisaurus"}

      Dim dinosaurs As New List(Of String)(input)

      outputBlock.Text += String.Format(vbLf & "Capacity: {0}", dinosaurs.Capacity) & vbCrLf

      outputBlock.Text &= vbCrLf
      For Each dinosaur As String In dinosaurs
         outputBlock.Text &= dinosaur & vbCrLf
      Next

      outputBlock.Text &= vbLf & "AddRange(dinosaurs)" & vbCrLf
      dinosaurs.AddRange(dinosaurs)

      outputBlock.Text &= vbCrLf
      For Each dinosaur As String In dinosaurs
         outputBlock.Text &= dinosaur & vbCrLf
      Next

      outputBlock.Text += String.Format(vbLf & "RemoveRange(2, 2)") & vbCrLf
      dinosaurs.RemoveRange(2, 2)

      outputBlock.Text &= vbCrLf
      For Each dinosaur As String In dinosaurs
         outputBlock.Text &= dinosaur & vbCrLf
      Next

      input = New String() {"Tyrannosaurus", _
                             "Deinonychus", _
                             "Velociraptor"}

      outputBlock.Text += String.Format(vbLf & "InsertRange(3, input)") & vbCrLf
      dinosaurs.InsertRange(3, input)

      outputBlock.Text &= vbCrLf
      For Each dinosaur As String In dinosaurs
         outputBlock.Text &= dinosaur & vbCrLf
      Next

      outputBlock.Text += String.Format(vbLf & "output = dinosaurs.GetRange(2, 3).ToArray") & vbCrLf
      Dim output() As String = dinosaurs.GetRange(2, 3).ToArray()

      outputBlock.Text &= vbCrLf
      For Each dinosaur As String In output
         outputBlock.Text &= dinosaur & vbCrLf
      Next

   End Sub
End Class

' This code example produces the following output:
'
'Capacity: 3
'
'Brachiosaurus
'Amargasaurus
'Mamenchisaurus
'
'AddRange(dinosaurs)
'
'Brachiosaurus
'Amargasaurus
'Mamenchisaurus
'Brachiosaurus
'Amargasaurus
'Mamenchisaurus
'
'RemoveRange(2, 2)
'
'Brachiosaurus
'Amargasaurus
'Amargasaurus
'Mamenchisaurus
'
'InsertRange(3, input)
'
'Brachiosaurus
'Amargasaurus
'Amargasaurus
'Tyrannosaurus
'Deinonychus
'Velociraptor
'Mamenchisaurus
'
'output = dinosaurs.GetRange(2, 3).ToArray
'
'Amargasaurus
'Tyrannosaurus
'Deinonychus

using System;
using System.Collections.Generic;

public class Example
{
   public static void Demo(System.Windows.Controls.TextBlock outputBlock)
   {
      string[] input = { "Brachiosaurus", 
                           "Amargasaurus", 
                           "Mamenchisaurus" };

      List<string> dinosaurs = new List<string>(input);

      outputBlock.Text += String.Format("\nCapacity: {0}", dinosaurs.Capacity) + "\n";

      outputBlock.Text += "\n";
      foreach (string dinosaur in dinosaurs)
      {
         outputBlock.Text += dinosaur + "\n";
      }

      outputBlock.Text += "\nAddRange(dinosaurs)" + "\n";
      dinosaurs.AddRange(dinosaurs);

      outputBlock.Text += "\n";
      foreach (string dinosaur in dinosaurs)
      {
         outputBlock.Text += dinosaur + "\n";
      }

      outputBlock.Text += String.Format("\nRemoveRange(2, 2)") + "\n";
      dinosaurs.RemoveRange(2, 2);

      outputBlock.Text += "\n";
      foreach (string dinosaur in dinosaurs)
      {
         outputBlock.Text += dinosaur + "\n";
      }

      input = new string[] { "Tyrannosaurus", 
                               "Deinonychus", 
                               "Velociraptor"};

      outputBlock.Text += String.Format("\nInsertRange(3, input)") + "\n";
      dinosaurs.InsertRange(3, input);

      outputBlock.Text += "\n";
      foreach (string dinosaur in dinosaurs)
      {
         outputBlock.Text += dinosaur + "\n";
      }

      outputBlock.Text += String.Format("\noutput = dinosaurs.GetRange(2, 3).ToArray()") + "\n";
      string[] output = dinosaurs.GetRange(2, 3).ToArray();

      outputBlock.Text += "\n";
      foreach (string dinosaur in output)
      {
         outputBlock.Text += dinosaur + "\n";
      }
   }
}

/* This code example produces the following output:

Capacity: 3

Brachiosaurus
Amargasaurus
Mamenchisaurus

AddRange(dinosaurs)

Brachiosaurus
Amargasaurus
Mamenchisaurus
Brachiosaurus
Amargasaurus
Mamenchisaurus

RemoveRange(2, 2)

Brachiosaurus
Amargasaurus
Amargasaurus
Mamenchisaurus

InsertRange(3, input)

Brachiosaurus
Amargasaurus
Amargasaurus
Tyrannosaurus
Deinonychus
Velociraptor
Mamenchisaurus

output = dinosaurs.GetRange(2, 3).ToArray()

Amargasaurus
Tyrannosaurus
Deinonychus
 */

Version Information

Silverlight

Supported in: 5, 4, 3

Silverlight for Windows Phone

Supported in: Windows Phone OS 7.1, Windows Phone OS 7.0

XNA Framework

Supported in: Xbox 360, Windows Phone OS 7.0

Platforms

For a list of the operating systems and browsers that are supported by Silverlight, see Supported Operating Systems and Browsers.